This study aims to examine the relationship between mood and brain activity in adolescent girls in order to better understand the genetic and neural predictors of adolescent depression. The participants in this study will be healthy female adolescents aged 12-14 and their mothers. They will participate for a total of six months. Adolescent participants will have three study sessions at McLean Hospital, and during two of them, their mothers will also have assessments. Adolescent assessments will include interviews, questionnaires, computer tasks, and collection of a saliva sample for genetic analyses. Their second study visit will include an fMRI scan. Parent assessments will include an interview, questionnaires, and a computer task.